1. Field of the Invention
The invention relates to a heater, especially a motor vehicle heater which can be operated independently of the engine, with a burner which is supplied with fuel and air via a binary nozzle, a combustion chamber, and a multistage compressor for compressing the air.
2. Description of Related Art
Binary nozzles usually have a concentric arrangement of a hole and an annular chamber, either the hole or the annular chamber being supplied with fuel by means of a metering pump and the fuel being atomized by the mass flow of air which is supplied via the other nozzle passage opening, the annular channel or the hole.
Furthermore, it is known, from published German Patent Application 2 135 093 and its counterpart U.S. Pat. No. 3,768,920, that the entire mass flow of air necessary for combustion in the heater is compressed by a two-stage flow machine and is delivered via a nozzle into the combustion chamber. The disadvantage here is that, for a large volumetric flow, a high pressure is necessary which causes correspondingly high energy consumption. The associated high flow speed in a binary nozzle would lead to starting problems, loud noise and high pressure losses.
Moreover, one such heater is known with a burner which has a binary nozzle in which the fuel atomization-air mass flow is compressed via a volumetric compressor to a higher pressure level separately from the other mass flow of air necessary for combustion. Here, the disadvantage is high costs, fault susceptibility, the corresponding maintenance cost of the compressor, and the loud noise of the compressor.